Piegrosast24 All details for the different prepaid plans, you can find here:
Prepaid: Mobile Tariffs & Prepaid Cards | Swisscom
prepaid basic ist without data, so you have to choose "Extended prepaid"
here you find for Prepaid plus:

there are different flats (with data) for a certain period of time (7, 30, 90 days) and also some data packages mentioned.